Discovery tga

Differential scanning calorimetry (DSC) was used to characterise the powders and the drug-loaded printlets at 100 mm/s, 120 mm/s, 140 mm/s,160 mm/s and 180 mm/s laser scanning speeds. DSC measurements were performed with a Q2000 DSC (TA instruments, Waters, LLC, USA) at a heating rate of 10 °C/min starting from 45 to 300 °C. Calibration for cell constant and enthalpy was performed with indium (Tm = 156.6 °C, DHf = 28.71 J/g) according to the manufacturer instructions. Nitrogen was used as a purge gas with a flow rate of 50 mL/min for all the experiments. Data were collected with TA Advantage software for Q series (version 2.8.394), and analysed using TA Instruments.
For thermogravimetric (TGA) analysis, samples (average weight: 3–5 mg) were heated at 10 °C/min starting from 30 to 400 °C in open aluminium pans with a Discovery TGA (TA instruments, Waters, LLC, USA). Nitrogen was used as a purge gas with a flow rate of 25 mL/min. Data were collected and analysed by using TA Instruments Trios software. The results from thermal analysis were plotted using MATLAB software version R2019a (The MathWorks, CA, USA).

Chemical composition of the scaffold was determined by Fourier transform infrared spectroscopy (FTIR, Perkin Elmer, FTIR-2000). For thermogravimetric analysis (TGA), samples were heated at 10 °C/min in open aluminium pans with a Discovery TGA (TA instruments, Waters, LLC, USA). Nitrogen was used as a purge gas with a flow rate of 25 ml/min. Data collection and analysis were performed using TA Instruments Trios software and % mass loss and/or onset temperature were calculated. The wide-angle X-ray diffraction (XRD) pattern of chitin powders and the dried sheets were recorded on an XRD instrument (D8ADVANCE, BRUKER, Germany) with Cu–K radiation (λ = 0.154 nm). The XRD data were collected from 2θ = 5 to 35° at a scanning rate of 2° min⁻¹. The mechanical properties of the scaffold were measured using a universal mechanical testing machine (Instron 1121, UK). Scanning electron microscopy (SEM) Surface and cross-section images of the filaments were taken with an SEM (JSM-840 A Scanning Microscope, JEOL GmbH, Eching, Germany).

A Bruker D8 diffractometer was used for X-ray diffraction (XRD) analysis. The sample’s morphology was analyzed by a XL 30 ESEM scanning electron microscopy (SEM) acquired from Philips (Amsterdam, The Netherlands). Active functional groups over the material’s surface were determined by Fourier transform infra-red (FT-IR) spectroscopy using a Nicolet 6700 Spectrometer (Thermo-Fisher Scientific, Massachusetts, USA). Thermal analysis was performed under N₂ atmosphere using a thermogravimetric analyzer Discovery TGA from TA instruments (Waters Corporation, New Castle, USA). The determination of the point of zero charge (pH_PZC) was done by the method described by Zaini et al. [33 (link)]. Briefly, 0.10 g of material was mixed with 50 mL of 0.01 M NaCl at different initial pHs (pH = 1, 2, 3, 4, 5, 6, 7, and 8). These pH values were adjusted by adding a small amount of 0.1 M HCl/NaOH solutions. The suspensions were allowed to equilibrate for 72 h under mechanical agitation at 25 °C, then centrifuged at 5000 rpm for 10 min, and the final pH of each supernatant was measured using a pH meter inoLab^® pH 7310 from Xylem Analytics (Weilheim, Germany).